1. Field of the Invention
The present invention relates generally to gauges and measuring devices used to determine correct pipe fitting angles for connecting a pair of offset pipes. More particularly, the present invention relates to a calculator graph for determining the correct angles for fabrication of a pipe fitting depending on an offset distance between a pair of pipes to be connected using the fabricated pipe fitting in conjunction with an ell fitting or a T-fitting.
2. Description of the Prior Art
Pipefitters typically install and maintain piping systems for a wide variety of applications. For example, piping systems are used in the production of electricity, chemicals and computer chips, as well as in heating and cooling applications. During the course of installing and maintaining a piping system, a pipe fitter typically must connect two pipes which are disposed in different planes as occurs, for example, when a first run of pipe is to be connected to a second run of pipe that is disposed at an elevation with respect to the first run. The difference in position between the pipes is referred to as an offset.
Most pipes in a piping system are connected using standard ell fittings or T-fittings which have arms disposed at 45 or 90 degrees with respect to each other to facilitate the change in piping direction or elevation. However, because of their fixed dimensions, standard fittings will not work under circumstances in which the offset does not define a standard 45- or 90-degree angle with respect to the pipes to be connected. For example, if two pipes to be connected are 12 inches apart and two standard 90-degree ell fittings are adapted for an 18-inch connection, the standard 90-degree fittings cannot be used for the connection. In many cases, the angle between two existing pipes is other than that of a conventional elbow of 45 or 90 degrees and must be measured precisely in order to fabricate an elbow of the proper angle. It thus becomes necessary to alter a standard ell fitting in order to connect two pipes having an unconventional offset with respect to each other. This unconventional connection requirement is referred to as a special offset. Finding the correct angle for the pipe fitting required to be used in conjunction with a standard fitting or two ells of the same degree for a special offset is difficult, and use of trigonometry is essential for this determination.
Several devices are known in the art for measuring the angle between a pair of pipes intersecting each other in the same plane in order to fabricate a fitting having the desired angle for connecting the pipes. One of these is the “Pipefitters's Protractor” described in U.S. pat. appl. publication no. 2002/0092191 A1. The pipefitter's protractor is used to measure the angle between two separate pipes having an intersecting point. The protractor assembly includes a pipe attachment bar secured to the squared end of one pipe, with a protractor arm extending from the center of the pipe attachment bar and concentric with the centerline of the pipe. The protractor extends from the arm, with the arm and protractor rotating about the pipe attachment bar fitting to align the protractor plate coplanar with the plane defined by the pipes. The protractor is adjusted along the protractor arm to position the protractor origin at the intersection of the pipe centerlines, and a line is run from the origin to the center of the second pipe. The angle between the pipes and the distances from the protractor origin to the ends of each pipe are then used for fabricating an elbow to join the pipes.